Why DDHQ hasn’t called the Pennsylvania Senate race

The Pennsylvania Senate race remains the last major contest of the 2024 cycle that Decision Desk HQ has not called.

Three-term incumbent Sen. Bob Casey (D) currently trails Republican Dave McCormick by about 35,000 votes, or 0.5 percent of the vote, just within the threshold required for an automatic statewide recount. But while McCormick has declared victory and The Associated Press has projected him as the winner, Casey hasn’t yet conceded and The Hill’s partner DDHQ and other networks have not issued a race call.

“We haven’t projected a winner in the Pennsylvania Senate election for the very simple reason that it doesn’t meet our stringent 99.5% or greater level of certainty before we can make a projection,” said Scott Tranter, the head of data science for DDHQ.

While more than 95 percent of votes cast are estimated to have been counted, Tranter said DDHQ believes somewhere between 80,000 and 115,000 provisional, military and overseas and domestic absentee ballots could be outstanding. The exact number is uncertain because of how counties report their votes, but these votes could heavily favor Casey, giving him a chance at pulling off a win.

“With McCormick's margin less than 40,000 votes and the potential for these ballots to break towards Casey in a significant way DDHQ needs to see more of these votes counted before a projection can be made,” Tranter said.

The race has become particularly contentious over the past week with Senate Majority Leader Chuck Schumer (D-N.Y.) initially declining to invite McCormick to the new members’ orientation this week. A spokesperson for him said Schumer would invite the winner once all the votes are counted, but the senator faced pushback from Republicans and various fellow members, including Sens. Kyrsten Sinema (I-Ariz.) and Susan Collins (R-Maine).

Schumer’s office soon after announced that McCormick had received an invitation for the orientation.

Casey’s campaign has maintained as more votes have come in that it is waiting for all votes to be counted as it has not given in to calls, particularly from Republicans, to concede.

“My priority has always been standing up for the people of Pennsylvania. Across our Commonwealth, close to 7 million people cast their votes in a free and fair election,” Casey said in a statement on Tuesday. “Our county election officials will finish counting those votes, just like they do in every election. The American democratic process was born in Pennsylvania and that process will play out.”

McCormick has meanwhile been emphasizing on his X account the various local Pennsylvania outlets that have declared him the winner, many of them based on AP’s call but not all.

While Republicans have already been projected to win the Senate, the outcome of the Pennsylvania race could be critical to deciding the functioning of the government for the next two years and how each party’s chances look heading into the 2026 midterm elections.